EP0617307A2 - Optische Abtastvorrichtung - Google Patents

Optische Abtastvorrichtung Download PDF

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Publication number
EP0617307A2
EP0617307A2 EP94104437A EP94104437A EP0617307A2 EP 0617307 A2 EP0617307 A2 EP 0617307A2 EP 94104437 A EP94104437 A EP 94104437A EP 94104437 A EP94104437 A EP 94104437A EP 0617307 A2 EP0617307 A2 EP 0617307A2
Authority
EP
European Patent Office
Prior art keywords
mirror
reflecting
angle
optical scanning
incident
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94104437A
Other languages
English (en)
French (fr)
Other versions
EP0617307A3 (en
Inventor
Kouzo C/O Nippon Avionics Co. Ltd. Tsuchimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Avionics Co Ltd
Original Assignee
Nippon Avionics Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Avionics Co Ltd filed Critical Nippon Avionics Co Ltd
Publication of EP0617307A2 publication Critical patent/EP0617307A2/de
Publication of EP0617307A3 publication Critical patent/EP0617307A3/en
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/10—Scanning systems
    • G02B26/105—Scanning systems with one or more pivoting mirrors or galvano-mirrors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/10—Scanning systems
    • G02B26/12—Scanning systems using multifaceted mirrors
    • G02B26/129—Systems in which the scanning light beam is repeatedly reflected from the polygonal mirror

Definitions

  • the present invention relates to an optical scanning apparatus using an optical scanning mirror and, more particularly, to an optical scanning apparatus capable of increasing a scanning angle.
  • an optical scanning apparatus using an optical scanning mirror for changing the direction of a reflected beam with respect to an incident beam changes the angle of the scanning mirror to perform predetermined scanning based on a principle of changing the angle of a reflected beam by 2 ⁇ upon a change in angle of a reflecting surface by a given angle ⁇ with respect to the incident beam.
  • Various types of optical scanning mirrors are available in accordance with forms for mechanically changing the angle of the scanning mirror.
  • the optical scanning mirrors are a polyhedral rotary mirror (e.g., a mirror having reflecting surfaces whose angles are equal to or different from each other) for changing the angle or angles of a plurality of scanning mirrors in one direction, a tuning fork for changing the angle of a scanning mirror set at each distal end face of a U-shaped fork by vibrations, a resonant scanner for swinging a scanning mirror by reciprocally pivoting a rotating shaft mounted with the scanning mirror in a plane including the rotating shaft, and the like.
  • a polyhedral rotary mirror e.g., a mirror having reflecting surfaces whose angles are equal to or different from each other
  • a tuning fork for changing the angle of a scanning mirror set at each distal end face of a U-shaped fork by vibrations
  • a resonant scanner for swinging a scanning mirror by reciprocally pivoting a rotating shaft mounted with the scanning mirror in a plane including the rotating shaft, and the like.
  • An optical scanning apparatus preferably has a large scanning angle because it is used as an image pickup unit in an apparatus for acquiring, e.g., an infrared thermal imagery.
  • the scanning angle is generally small, and it is difficult to increase it because the optical scanning mirror mechanically changes the angle of the scanning mirror.
  • the scanning angle of the polyhedral rotary mirror depends on a mechanical rotation angle.
  • a regular hexahedral mirror restores its original shape upon rotation of 60°, and the limit of the mechanical scanning angle is 60°.
  • the number of reflecting surfaces must be reduced. This causes an increase in air resistance and degradation of scanning efficiency.
  • a regular trihedral mirror has a maximum scanning angle of 120°, and its air resistance is much higher than that of the regular hexahedral mirror.
  • the number of scanning cycles per revolution of the regular trihedral mirror is half that of the regular hexahedral mirror, thereby degrading the scanning efficiency.
  • the scanning angle can be increased by increasing an angle of change in the scanning mirror or utilizing multiple reflection.
  • a dynamic load acting on the scanning mechanism undesirably increases to pose a mechanical problem.
  • a scanning mirror 2 is changed from a parallel state indicated by a chain double-dashed line to have an angle ⁇ with respect to a stationary plane mirror 1, as shown in Fig. 3.
  • An incident ray X is repeatedly reflected between the stationary plane mirror 1 and the scanning mirror 2.
  • the directions of rays Y1, Y2,... reflected by the scanning mirror 2 are changed by 2 ⁇ for the first reflection and 4 ⁇ for the second reflection with respect to the directions of rays reflected when the stationary plane mirror 1 is parallel to the scanning mirror 2.
  • n-time reflection on the scanning mirror provides a scanning angle 2n times the mechanical change angle ⁇ in principle.
  • the second and subsequent reflection points are shifted with changes in scanning angle, thus undesirably requiring a large scanning mirror.
  • the shift amount of the reflection point increases to increase a dynamic load as in the above method of increasing the change angle of the scanning mirror.
  • an optical scanning apparatus comprising an optical scanning mirror, having a first reflecting surface for reflecting an incident beam and a second reflecting surface for reflecting the incident beam and causing the incident beam to emerge, for synchronously changing angles of the first and second reflecting surfaces in a predetermined direction, a reflecting mirror, arranged in an optical path between the first and second reflecting surfaces, for forming a double-reflection path, and a lens system, arranged in the double-reflection path, for causing a beam reflected by the first reflecting surface to be incident on the second reflecting surface at a predetermined angle.
  • Fig. 1 shows an optical scanning apparatus according to the first embodiment of the present invention.
  • the apparatus of the first embodiment utilizes a regular octahedral mirror 10 as an optical scanning mirror. States obtained by pivoting the regular octahedral mirror 10 three times by a predetermined angle ⁇ each are superposed in Fig. 1.
  • a reflecting surface A of the eight reflecting surfaces serves as an incident surface, and a reflecting surface B serves as an exit surface.
  • a reflecting mirror 20 has a cross-sectional shape of an isosceles triangle and is constituted by bonding two right-angle mirrors 21 and 22 respectively having incident surfaces 21a and 22a, reflecting surfaces 21b and 22b, and exit surfaces 21c and 22c.
  • the incident surface 21a of the right-angle mirror 21 receives a beam reflected by the reflecting surface A of the regular octahedral mirror 10, and the exit surface 22c of the right-angle mirror 22 causes an exit beam to emerge to the reflecting surface B of the regular octahedral mirror 10.
  • Convex lenses 31 and 32 each having a predetermined focal length are disposed as focusing means at the incident surface 21a of the right-angle mirror 21 and the exit surface 22c of the right-angle mirror 22, respectively.
  • Reference numeral 40 denotes a laser source for emitting a laser beam.
  • the laser beam from the laser source 40 is incident as a parallel beam having a predetermined diameter on the reflecting surface A of the regular octahedral mirror 10 and reflected toward the reflecting mirror 20.
  • the laser beam from the laser source 40 and reflected by the reflecting surface A of the regular octahedral mirror 10 is incident on the incident surface 21a of the right-angle mirror 21.
  • the laser beam is focused by the lens 31 and guided inside the reflecting mirror 20.
  • the laser beam is reflected by the reflecting surface 21b located deep inside the reflecting mirror 20.
  • the laser beam is incident on the incident surface 22a of the right-angle mirror 22 to be almost parallel to the incident surface 21a.
  • the laser beam is then reflected by the reflecting surface 22b located deep inside the reflecting mirror 20.
  • the laser beam is focused by the lens 32 at the exit surface 22c of the right-angle mirror 22 and incident on the reflecting surface B of the regular octahedral mirror 10.
  • the laser beam is then reflected by the reflecting surface B and emerges as a scanning laser beam corresponding to the rotation angle of the regular octahedral mirror 10.
  • the two lenses 31 and 32 constitute a telescope.
  • the angle change direction of the reflecting surface A is the same as that of the reflecting surface, so that the telescope serves as an inverted telescope.
  • a laser beam from the laser source 40 is reflected by the reflecting surface A of the regular octahedral mirror 10 and serves as a reflected beam as indicated by a chain line in Fig. 1.
  • the reflected beam passes through the lens 31 portion corresponding to the outer portion of the reflecting mirror 20 and is incident on the reflecting mirror 20.
  • This beam passes through the lens 32 portion corresponding to the outer portion of the reflecting mirror and emerges outside the reflecting mirror 20.
  • the exit beam from the reflecting mirror 20 is reflected by the reflecting surface B of the regular octahedral mirror 10 and emerges in a direction indicated by an arrow E.
  • a laser beam from the laser source 40 is reflected by the reflecting surface A of the regular octahedral mirror 10 at a scanning angle 2 ⁇ and serves as a reflected beam indicated by a solid line in Fig. 1.
  • This reflected beam passes through the center of the lens 31 and is incident on the reflecting mirror 20. The beam then passes the central portion of the lens 32 and emerges from the reflecting mirror 20.
  • the exit beam from the reflecting mirror 20 is reflected by the reflecting surface B of the regular octahedral mirror 10 at a scanning angle 4 ⁇ and emerges in a direction indicated by an arrow F.
  • a laser beam from the laser source 40 is reflected by the reflecting surface A of the regular octahedral mirror 10 at a scanning angle 4 ⁇ and serves as a reflected beam indicated by a solid line. This beam passes through the lens 31 portion corresponding to the inner portion of the reflecting mirror 20 and is incident on the reflecting mirror 20.
  • the beam then passes through the lens 32 portion corresponding to the inner portion of the reflecting mirror 20 and emerges from the reflecting mirror 20.
  • the exit beam from the reflecting mirror 20 is reflected by the reflecting surface B of the regular octahedral mirror 10 at a scanning angle 8 ⁇ and emerges in a direction indicated by an arrow G.
  • the beams reflected by the reflecting surface A of the regular octahedral mirror 10 are returned to the reflecting surface B of the regular octahedral mirror 10 by an optical system constituted by a combination of the reflecting mirror 20 and the lenses 31 and 32 constituting the inverted telescope, all the beams reflected by the reflecting surface A at the corresponding scanning angles are focused on the reflecting surface B.
  • the incident angle change direction on the reflecting surface B is the same as the rotational direction of the regular octahedral mirror 10 constituting the scanning mirror by means of the inverted telescope, the scanning angle of the beam reflected by the reflecting surface B is always twice the scanning angle on the reflecting surface A, provided that the inverted telescope has a magnification of 1.
  • a shift in reflecting point can be eliminated due to the operation of the optical system, unlike the conventional case. That is, according this embodiment, the shift in reflection point can be eliminated.
  • the scanning angle can increase without increasing the mechanical scanning angle.
  • the scanning angle can further increase due to an amplification effect by the magnification of the telescope.
  • the laser beams on the reflecting surfaces A and B of the regular octahedral mirror 10 are illustrated in an enlarged manner in Fig. 1.
  • the diameter of a circumscribed circle for the regular octahedral mirror 10 is 40 mm, and the diameter of a parallel beam is 5 mm.
  • the relationship between the rotation angle and the beam is also illustrated. In general, when a rotary scanning mirror is used, the rotation angle is limited by the diameter of the beam and the size and shape of the polyhedral mirror.
  • Fig. 2 shows an optical scanning apparatus according to the second embodiment of the present invention.
  • the apparatus of the second embodiment uses a Y-shaped tuning fork 121 having forks 121a and 121b as an optical scanning mirror.
  • Reflecting surfaces A and B inclined in oppose directions at the same angle are formed on the distal end faces of the forks 121a and 121b of the tuning fork 121.
  • a proximal portion 121c of the tuning fork 121 is electromagnetically vibrated, as indicated by an arrow C
  • the forks 121a and 121b resonate each other on the same plane but in opposite directions, as indicated by a double-headed arrow D.
  • the reflecting surfaces A and B are inclined at the same angle ⁇ but in the opposite directions.
  • An optical system consisting of two plane mirrors 122 and 123 constituting a reflecting mirror and four lenses 124 to 127 constituting a telescope is arranged with respect to this tuning fork 121.
  • a scanning angle 2 ⁇ on the reflecting surface A is amplified as a scanning angle 4 ⁇ on the reflecting surface B as in the first embodiment.
  • the telescope (124 to 127) serves as an erecting telescope unlike the first embodiment because the angle change directions of the two reflecting surfaces A and B are opposite to each other.
  • a resonant scanner can be used as an optical scanning mirror.
  • two resonant scanners are prepared and synchronously rotated.
  • the angle change directions of the two scanning mirrors are opposite to each other to facilitate light beam incidence and emergence because the layout positions of the two scanning mirrors are physically determined in the tuning fork, the rotational direction of the rotating shafts of the two resonant scanners are the same or opposite.
  • the present invention is applicable to a conventional general scanning mirror.
  • the inverted or erecting form is selected in accordance with whether the angle change directions of the two reflecting mirrors utilized in this scanning mirror are the same or opposite, thereby increasing the optical scanning angle.
  • the angular change amounts of the two reflecting mirrors are equal to each other, but can be different from each other.
  • a beam reflected by one reflecting surface of a conventional general optical scanning mirror (e.g., a rotary polyhedral mirror, a tuning fork, or a resonant scanner) is incident on the other reflecting surface by an optical system constituted by a combination of a reflecting mirror and a telescope. That is, double-reflection can be realized by the above optical system.
  • a conventional scanning system having a limited scanning angle the scanning angle can be easily and greatly increased. In other words, a necessary mechanical scanning angle can be reduced into 1/2 to obtain a given specific scanning angle. Therefore, the apparatus having the scanning mirror as the major component can be made compact, and its power consumption can be reduced.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Optical Scanning Systems (AREA)
  • Telescopes (AREA)
EP94104437A 1993-03-24 1994-03-21 Optical scanning apparatus. Withdrawn EP0617307A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP89375/93 1993-03-24
JP5089375A JPH06273683A (ja) 1993-03-24 1993-03-24 光学走査装置

Publications (2)

Publication Number Publication Date
EP0617307A2 true EP0617307A2 (de) 1994-09-28
EP0617307A3 EP0617307A3 (en) 1995-10-18

Family

ID=13968946

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94104437A Withdrawn EP0617307A3 (en) 1993-03-24 1994-03-21 Optical scanning apparatus.

Country Status (4)

Country Link
EP (1) EP0617307A3 (de)
JP (1) JPH06273683A (de)
KR (1) KR940022119A (de)
CN (1) CN1031671C (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0775928A2 (de) * 1995-11-24 1997-05-28 Seiko Epson Corporation Optischer Scanner
EP0825468A2 (de) * 1996-08-21 1998-02-25 Seiko Epson Corporation Optisches Abtastgerät
EP1031866A2 (de) * 1999-02-18 2000-08-30 CARL ZEISS JENA GmbH Relaisoptik für ein Ablenksystem sowie ein Ablenksystem

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3922382B2 (ja) * 1995-11-24 2007-05-30 セイコーエプソン株式会社 光走査装置
JP4701593B2 (ja) * 2003-08-21 2011-06-15 セイコーエプソン株式会社 光走査装置および画像形成装置
JP4576816B2 (ja) * 2003-09-17 2010-11-10 セイコーエプソン株式会社 光走査装置および画像形成装置
JP7247618B2 (ja) * 2019-02-05 2023-03-29 富士電機株式会社 光走査装置及び光走査方法
CN118091706B (zh) * 2024-04-23 2024-07-12 深圳大舜激光技术有限公司 一种基于激光雷达的多望远镜阵列快速扫描测量系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4251125A (en) * 1976-12-28 1981-02-17 Canon Kabushiki Kaisha Scanning optical system including an afocal system
US4299438A (en) * 1977-02-04 1981-11-10 Canon Kabushiki Kaisha Scanning optical system having at least two reflecting surfaces and an afocal optical system
JPS60107016A (ja) * 1983-11-15 1985-06-12 Anritsu Corp 入射光束から平行な走査光束を得る装置
JPS62226119A (ja) * 1986-03-27 1987-10-05 Seiko Epson Corp 光スキヤナ−
JPH0254212A (ja) * 1988-08-19 1990-02-23 Nec Corp 光学スキャナ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4251125A (en) * 1976-12-28 1981-02-17 Canon Kabushiki Kaisha Scanning optical system including an afocal system
US4299438A (en) * 1977-02-04 1981-11-10 Canon Kabushiki Kaisha Scanning optical system having at least two reflecting surfaces and an afocal optical system
JPS60107016A (ja) * 1983-11-15 1985-06-12 Anritsu Corp 入射光束から平行な走査光束を得る装置
JPS62226119A (ja) * 1986-03-27 1987-10-05 Seiko Epson Corp 光スキヤナ−
JPH0254212A (ja) * 1988-08-19 1990-02-23 Nec Corp 光学スキャナ

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 009 no. 257 (P-396) ,15 October 1985 & JP-A-60 107016 (ANRITSU DENKI KK) 12 June 1985, *
PATENT ABSTRACTS OF JAPAN vol. 012 no. 093 (P-680) ,26 March 1988 & JP-A-62 226119 (SEIKO EPSON CORP) 5 October 1987, *
PATENT ABSTRACTS OF JAPAN vol. 014 no. 226 (P-1047) ,14 May 1990 & JP-A-02 054212 (NEC CORP) 23 February 1990, *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0775928A2 (de) * 1995-11-24 1997-05-28 Seiko Epson Corporation Optischer Scanner
EP0775928A3 (de) * 1995-11-24 1999-04-21 Seiko Epson Corporation Optischer Scanner
EP1195636A2 (de) * 1995-11-24 2002-04-10 Seiko Epson Corporation Optischer Scanner
EP1195636A3 (de) * 1995-11-24 2004-05-26 Seiko Epson Corporation Optischer Scanner
EP0825468A2 (de) * 1996-08-21 1998-02-25 Seiko Epson Corporation Optisches Abtastgerät
EP0825469A2 (de) * 1996-08-21 1998-02-25 Seiko Epson Corporation Optisches Abtastgerät
EP0825468A3 (de) * 1996-08-21 1999-04-21 Seiko Epson Corporation Optisches Abtastgerät
EP0825469A3 (de) * 1996-08-21 1999-05-06 Seiko Epson Corporation Optisches Abtastgerät
EP1031866A2 (de) * 1999-02-18 2000-08-30 CARL ZEISS JENA GmbH Relaisoptik für ein Ablenksystem sowie ein Ablenksystem
EP1031866A3 (de) * 1999-02-18 2003-11-26 CARL ZEISS JENA GmbH Relaisoptik für ein Ablenksystem sowie ein Ablenksystem

Also Published As

Publication number Publication date
EP0617307A3 (en) 1995-10-18
JPH06273683A (ja) 1994-09-30
CN1031671C (zh) 1996-04-24
CN1096589A (zh) 1994-12-21
KR940022119A (ko) 1994-10-20

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